In the medical and surgical fields, intravenous (IV) fluids are generally administered to a patient through a catheter inserted into a vein of the patient. The catheter is typically coupled to an IV connector, which is connected by IV tubing to a container of IV fluid.
Generally the catheter includes an insertion end and a connecting end configured as a female fitting having a diameter substantially larger than the catheter itself. A cooperating connector has a male fitting portion adapted to mate with the female fitting. The female and male fittings are commonly configured as luer lock type fittings. As luer fittings, the male portion of the IV connector has a precise tapered outer surface, and the catheter's aperture has a similarly tapered female bore. When assembled, the tapered male and female surfaces engage in a slip type interference fit to frictionally fit the catheter and connector together. A fastening means is provided to lock the catheter and connector together.
By design, the threaded collar or female catheter has a larger outside diameter than the male connector, catheter and associated medical tubing connected thereby to the catheter. Problematically however, the relatively larger diameter of the connector portion causes the assembled catheter and connector to teeter, or rock, back and forth about the centerline of the connector. This teetering effect can cause patient discomfort, and some loosening of dressings holding the catheter in place, when the catheter is inserted in a patient.
Additionally, this teetering or rocking about the connector can cause in-and-out movement of the catheter tip causing vessel wall damage, or even full infiltration of the catheter tip through the vessel wall.